These proceedings contain the papers presented at ECIR 2009, the 31st - ropean Conference on Information Retrieval. The conference was organized by the Institut de Recherche en Informatique de Toulouse (IRIT), in cooperation with the Information Retrieval Specialist Group of the British Computer So- ety (BCS-IRSG) and was supported by the Special Interest Group on Infor- tion Retrieval (ACM SIGIR), the French Association of Information Retrieval (ARIA) and E-IRSG. It was held during April 6-9, 2007 in Toulouse, hosted by the Pierre Baudis congress center. ECIR 2009 con?rmed the growth trend...